This research entails an analysis of the immunology of early-generation transplantable derivatives of ethylnitrosourea-induced F-344 rat malignant gliomas. More specifically, by means of in vivo tumor rejection assays and Winn tumor neutralization tests, the aims are (a) to determine if these gliomas express individually-unique or cross-reactive tumor-specific transplantation antigens, (b) to measure the extent to which the afferent and efferent limbs of cellular immunity are active against these tumors when they are grafted in the brain, (c) to explore whether BCG-priming/PPD-coupling are effective methods of augmenting immunologically-mediated rejection of glioma transplants in either subcutaneous or intracerebral sites, and (d) to clarify the role of thymus-derived cells in mediating either tumoricidal anti-glioma immunity or tumor growth-enhancing processes.